How Long Does Marijuana Stay in Your System?

Overview: How long does it take to get weed out of your system for a drug test?

Thc lasts in your body a maximum of about 30 days as a rule of thumb.  It will be detectable in hair for up to 90 days.

Marijuana detection time chart

How Long To Get THC out your system: abstain for the following detection windows
Test TypeSalivaBloodUrineHairSweat
Infrequent user: how long one joint lasts in your systemAbout 24 hours1-2 days7 daysUndetectable up to 90 days1 to 4 weeks
Moderate use: twice per week, herbal weed smoke of medium concentrations1 to 3 days3 days10-18 days90 days1 to 4 weeks
Daily use of herbal and/or edibles and concentrates3 days after ceasing use7 days30 to 48 days90 days1 to 4 weeks

How THC is metabolized

In the body, THC will be metabolized into 11-OH-THC.  This metabolite is still an active drug.  It will then be further metabolized into 11-nor-9-carboxy-THC or THC-COOH.  This metabolite will hide out in the fat cells and be slowly released into the bloodstream.  From there it will reach the urine and small amounts (undetectable) will leech into the saliva.  The type of THC tested for by saliva tests is the unmetabolized form that comes directly from smoking.  Further, metabolized THC will go from the bloodstream into the sweat and hair.

Factors that influence how long weed stays in the system

Smoking frequency

If you smoked just one joint one time, it may be out of your system as soon as 24 hours.  If you take powerful edibles daily, you would want to abstain for as long as one month to have a chance of testing clean.

THC content and route of administration

Eating your cannabis will give a slower but more concentrated hit of THC.  Eating may spike blood and urine levels later but more intensely than smoking.  Smoking powerful concentrates like dabs will cause a quick spike of THC, but it will likely leave the body quicker.

Body Fat Content

Since THC hides out in the fat cells, if you have a lot of fat cell volume, you may store more THC.  Also, if you suddenly start burning a lot of fat, you may end up with a spike of THC metabolites in the bloodstream and urine.


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Types of drug tests

Urine: How long does it take the pot to leave the system for a urine drug test?

THC stays in the urine for a maximum of about 30 days.  Weed gets out of your pee at a rate that is slower than that of saliva, which is similar to the rate it leaves the blood, and sooner than hair.  Cannabis is detectable in urine so long as THC is spilling from fat cells, into the blood, then into the urine.  This will be the case so long as the urine is concentrated enough for tests to detect the major metabolite of THC in urine, THCCOOH.

The best way to clean your system for a urine drug test is to use a process called dilution.  But first, let’s make a distinction.  Dilution does not actually remove marijuana from your system any faster than normal, as far as we know. Instead, it merely dilutes the drug metabolites so that they are less easy to detect. A good dilution regimen then adds creatine, b-vitamins, and electrolytes to the urine by ingesting them about 2 hours prior to the urine drug test, as these will be looked for by the drug testers to rule out a dilute sample.

Science: Can a urine test be beaten?

A study in the Journal of Addiction Medicine concludes concerning dilute urine samples:

“This study supports the theory that urine dilution is not a random happening and it may adversely affect the integrity of the drug-testing process.”[i]

They discovered some samples were diluted but still contained enough creatinine and other correct values to be valid.  Their analysis revealed this is unlikely to be random, from people simply having a drink before the test.  It is evidence of intentional and effective dilution to beat a drug test.

Hair: How long is marijuana detectable in your hair follicles?

Generally, weed will show up on a hair follicle drug test for 90 days after the last use. However, the ‘hair follicle’ drug test is a misnomer. Since the hair is cut at the scalp and the first 1.5 inches measured, the hair follicle is left on the scalp. What is tested is the hair shaft. The drug residues are deposited inside of the cuticle.

Test & Analysis Methods

During the test itself, a small amount of hair is cut and taken for analysis. A hair follicle test is usually undertaken using a two-step process. First, an enzyme-linked immunosorbent assay test or ELISA test is used. This test measures how, if present, toxins such as drug residues are interacting with antibodies to in turn show whether or not there are drug residues present. The second phase of testing comes in the form of a gas chromatography-mass spectrometry (GC-MS) test which is designed to rule out a false positive. The purpose of a GC-MS test is to separate the various substances from the sample so that specific substances such as drug residues, if present in the sample, can be detected more easily and proven to be there in the case that the ELISA test first came up as positive.

Beating a hair follicle test is especially difficult because it can detect drugs taken in the 90 days previous to the day of testing. However, like with any drug test, it is possible.[ii]  A study in Drug Test Analysis compared several detox shampoos to see if they could remove alcohol metabolites from the hair.  Each shampoo and deionized water removed some drug metabolites.  However, one shampoo fared even better.  “The fourth shampoo showed additional heavy washout effects with a decrease of up to 86% after 2.5 hours.”[iii]  This was sufficient to produce a false negative result that users are seeking. This, in turn, proved scientifically that beating a hair follicle test, at least in one form, is possible.

A study in the International Journal of Legal Medicine tested a detox shampoo called Ultra Clean to see if it removed drug metabolites from the hair. They discovered, “…a slight decrease in drug concentrations could mostly be observed e.g. cocaine (n = 10) -5%, 6-MAM (n = 12) -9%, morphine (n = 12) -26%, THC (n = 4) -36%. The findings clearly demonstrated that drug substances had not been sufficiently removed from human hair by a single Ultra Clean treatment to drop their concentrations below the limit of detection of the analytical method applied.”[iv] In other words, the shampoo did remove metabolites, but not enough to test negative.  However, if washed more than once or with a method like the Macujo or Jerry G Method, it may remove enough drug metabolites for a negative hair drug test. It has also been discovered that cosmetic hair treatments like bleaching and dyeing as well as perming can cause negative results in hair tests despite drug use.[v] [vi]


Saliva drug test detection times extend to a window of only up to 3 days.  Most drugs will no longer be detectable from fluid from the salivary glands within just 24 hours after use.

Analysis Methods

According to The Clinical Biochemical Review, “Confirmatory techniques are largely based on mass spectrometry (MS) with an emphasis on Liquid Chromatography-Mass Spectrometry (LC-MS).”[vii] First a High-Performance Liquid Chromatography is used to separate substances within a sample before a Mass Spectrometer is utilized for analyzing these given substances to determine whether or not drug toxins are present in the sample.

Science: Can it be beaten?

Asked if home remedies like baking soda and salt mouthwashes work to beat a saliva drug test, Amitava Dasgupta, Ph.D., a professor specializing in Toxicology at the University of Texas-Houston Medical Center stated, “Does it work? Yes, it does.  It’s a cat and mouse game.”[viii]  Since the professor is neither affiliated with drug testing companies, nor the detox companies trying to beat their drug tests, the professor told it like it is.

Blood: How long is marijuana in the bloodstream?

Weed stays in your blood system generally for up to 30 days after last use, but only at very low, possibly undetectable levels.  Weed spikes and is detectable in the blood only within about six hours of use.

Testing Process

An experienced phlebotomist needs to withdraw the blood with a needle to avoid infection or collapsed veins.  She will then clean and bandage the area.

Analysis Methods

ELISA is used to analyze the blood sample. A positive sample might be confirmed with a mass spectrometry method.  Blood tests are infrequently used because they are expensive and invasive.  The prick of the needle can cause infection[ix].

Can it be beaten?

Blood tests are difficult to beat intentionally because it’s difficult to add any substance to the blood.  However, blood levels of THC only remain high for about the first 6 hours after use.  After that, there’s only a slow trickle of THC in the blood, which ends up in the urine.  However, in the urine, it’s concentrated within just 3 ounces of fluid, whereas in the blood it is diluted in gallons of blood and therefore unlikely to be detected.


Marijuana can stay in your system for a longer period than most drugs. The frequency at which you smoke, your body weight and a range of other factors can also influence how long THC toxins and its metabolites will remain in your body. The duration for which they can remain detectable varies depending on the test, with saliva tests picking up weed that has been consumed in the past 2-3 days, while hair follicle tests may be capable of detecting THC for 90 days following your last smoke or longer. A variety of techniques are used for the various types of drug tests but in general, it is possible to beat them, with the exception of blood tests done within 6 hours of weed use. Following the right method or/and product is the key to success. There is no guarantee either way that you will pass a test using a given product or/and approach but some options will give you better odds than others and undertaking the right research can make a big difference in terms of maximizing your chances of beating a drug test. If you choose to use a detox product in order to cheat a drug test, make sure that it is legal to do so in your region as some territories including 9 U.S. states have outlawed this practiceReferences

[i] “Dilution of urine drug tests: is it random? – NCBI.” Accessed 10 Mar. 2020.

[ii] “Detox shampoos for EtG and FAEE in hair – Results from in ….” 5 Feb. 2019, Accessed 10 Mar. 2020.

[iii] “Detox shampoos for EtG and FAEE in hair – Results … – NCBI.” 5 Feb. 2019, Accessed 10 Mar. 2020.

[iv] “Effect of the shampoo Ultra Clean on drug concentrations in ….” Accessed 10 Mar. 2020.

[v] “Influence of the cosmetic treatment of hair on drug testing..” Accessed 10 Mar. 2020.

[vi] “(PDF) Pitfalls in hair analysis: Cosmetic treatment.” 3 Feb. 2014, Accessed 10 Mar. 2020.

[vii] “Drug testing in oral fluid. – NCBI.” Accessed 10 Mar. 2020.

[viii] “Drug-Test Cheats Try New Tricks on Labs – WebMD.” 28 Jul. 2008, Accessed 10 Mar. 2020.

[ix] “objective testing – urine and other drugs….” 30 Mar. 2016, Accessed 10 Mar. 2020.

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